FEATURES AND HEAT-RESISTANCE OF SHICAI (Brassica campestris) TETRAPLOIDS

Zhang Jianjun;Yin Liqing;Zhang Weiping; Gu JinyanZhang Zhiqi; Fan Kunhua; Chen Quanqing; Zhong Weijin(Shanghai Academy of Agricultural Sciences,Shanghai 201106 )

Shicai (Brassica campestris ); Tetraploid feature; Strain; Heat resistance;Characters

Big cotyledon,wide petal,deep leaf color,small leaf length/leaf width value,low seed-setting rate and high 1 000-grain weight are the significant features of 48 tested Shicai (Brassica campestris)tetraploid lines. The lowest and highest chlorophyll contents in theselines are 1. 2 and 2 times as high as those of the diploid CK,respectively. As compared to theCK, these tetraploid lines show an higher average value for the total amino acid content(9. 35% higher), higher average values for 12 of the total 16 amino acids, higher individualvalues for 5 of the 12 amino acids and lower average values for 4 other amino acids. About25% of these tetraploid lines are possessed of heat resistance. The growth potential is betterfor the heat-resistant lines than for the CK in summer,the average outputs of these lines in 3treatments by dense sowing for use as pakchoi seedlings, direct seeding or transplant are107. 51 %, 141. 00% or 132. 00% of the average outputs of the CK,respectively, The leavesof the heat-resistant lines were fewer than those of the CK,so the giantism was the main factor of high yield for these lines. There are some genetic diversity among different tetraploidlines and a relative genetic stability within any tetraploid line.